Improvement in compositions for covering blackboards



UNITED STATES PATENT OFFICE.

NATHAN V. EVANS, OF WINSLOW, INDIANA, ASSIGNOR TO. HIMSELF AND -JOEL B. EVANS, OF SAME PLACE.

IMPROVEMENT IN COMPOSITIONS FOR COVERING BLACKBOARDS, 8co- Specification forming part of Letters Patent No. 122,763, dated January 16, 1872.

' globes, 820., for the purpose of giving them a Writing surface adapted for chalk or slate-pencil.

The ingredients of which my compound is composed are as follows: One (1) gallon alcohol; one and one-half (1%) pounds gum shellac;

one (1)poundflourof emery; one-half (:1?) pound ivory black. Umber maybe used instead of ivory black, if desired.

- Theseingredientsshouldbethoroughlylnixed together before being used. They may be applied to any proper surface by means of a paint or other brush. The surface after being coated should be dressed smooth with sand-paper.

The surface thus made, when dry, may be written upon by a common slate-pencil. If the surface isdesigned exclusively for chalk onehalf of the emery may be dispensed with.

Thiscompound possessesmarkedadvantages over any in use, inasmuch as it furnishes a better and more durable surface.

I am aware of the patent of W. W. Dudley, in which patent pumice-stone is used as a base; but a compound made with such a base and in accordance With said patent is practically of little value because the surface soon becomes glossy and refuses the chalk.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

A compound for covering blackboards, &c., composed of the ingredients named.

This specification signed and witnessed this 10th day of August, 1871.

NATHAN V. EVANS.

Witnesses:

J. W. RICHARDSON,- D. C. ASHBY. 

